Cooling firefighters

February 1, 2008 — Safety scientists used principles of physiology to help keep firefighters cool in the high temperature environments they often encounter. Traditional firefighting gear considers the heat of the fire, but not the body heat generated by the firefighter. By running tubes of circulating cool water close to the skin, where the body brings warm blood, the suit pulls more heat away from the body. The suit focuses on areas where the body transfers the most heat – the scalp, chest, and forearms. See also: Matter & Energy Civil Engineering Construction Weapons Technology Materials Science Physics Nature of Water Reference Firestorm Combustion Gas laws Sulfur hexafluoride Firefighters battle flames and smoke in gear that is specially designed to insulate them -- even when temperatures exceed one thousand degrees. But the very same life-saving equipment a firefighter dons may be putting him or her at risk -- by raising body temperatures to dangerous levels. Now researchers are developing a system to cool them off while they're smack dab in the middle of the fire. Firefighting is dangerously hot work. The heat from a house fire can reach over 11-hundred degrees Fahrenheit. "It causes you to build up body heat," Jon Williams, Research Physiologist at the National Institute for Occupational Safety and Health told Ivanhoe. But soon -- firefighters may add another layer of protection that will subtract body heat. This is a cooling suit -- a spandex undergarment, lined with plastic tubing. Physiologists say when a firefighter starts to work hard. His body gets rid of heat by moving warm blood into the skin. These tubes allow cool water to carry the heat away from the firefighter's body. The suit is designed to concentrate on areas where the body transfers the most heat. "The scalp, the areas of the chest, the forearms. Where you get more heat transfer in those areas than you would if you were cooling another area of the body," Williams said. At the National Institute for Occupational Safety and Health Lab, volunteers test the suit -- by walking on a treadmill -- to raise the person's core body temperature. For this test, researchers turned on the water transfer system. The volunteer's temperature barely changed. For the second test, the cooling system was not turned on. After just a few minutes, the monitor showed a temperature spike -- his body went from ninety-seven -point-seven degrees Fahrenheit to ninety-eight-point- seven. So now, scientists hope firefighters can douse flames … and keep cool all at the same time. Hotter Houses: House materials inside and out have changed dramatically over the last three decades -- most are now made from synthetic materials rather than wood or metal. So today's blazes produce two to three times as much energy as a typical fire did in 1980, and most of that energy is released as flammable gases. The invisible gases produced in a fire can be much more dangerous than the flames, especially in enclosed spaces. Newer buildings are well insulated and tightly sealed. That means gases in newer buildings can become superheated, flammable and highly mobile. The result is extreme fire behavior, marked by life-threatening backdrafts, flashovers and gas explosions. Scores of firefighters die each year because they use old outdated methods against this volatile mix of physics and fire gases. The American Industrial Hygiene Association and the National Institute for Occupational Safety and Health contributed to the information contained in the video portion of this report.

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